The nature of colonialism is examined in this comparison of British colonial policy in Ireland and Canada toward Indigenous people. The histories and realities of Indigenous peoples’ experiences of colonizing violence are not adequately addressed by the dominant approaches of the democratic peace theory’s universalist neoliberal technocratic values, expectations, and assumptions (see Mac Ginty, 2013). PACS scholars and practitioners need new interpretive frames to make sense of the impact and consequences of colonialism and the intent of genocidal destruction across different colonial contexts in order to understand the deep roots of conflict (economic exploitation, internalization of oppression, racist ideology), and how we should go about critical and emancipatory peace building, theory building, and practice. The study of colonialism is required to understand conflict milieus characterized by structural violence in order to create a justpeace (see Lederach, 1997) that includes restorative and reconciliatory processes, and recognition of local people’s resilience and resistance to structural violence and social injustice (see Chandler, 2017).